There are several preceding inventions related to electrical pneumatic vacuum flask as follows: U.S. application Nos. 332, 092; 459, 807; 665, 435; 798, 668; 384, 054; and 629, 351 which have been granted as U.S. Pat. Nos. 3,825,156; 3,905,520; 4,060,182; 4,116,366; 4,517,445; and 4,512,246, respectively. (Please refer to copies of U.S. Patent Publications attached hereto.) The above electrical or manual vacuum flasks all include button switches or pressing lids which are not disposed adjacent to the spouts and therefore, the water contained therein must be discharged by means of turning on the switch or pressing the lid with one hand.
In case of a button switch (such as U.S. application No. 798,668), the motor 14 will be activated right after pressing the button switch, making the pump 11a vertically reciprocate to pump air into the intermal vessel 1. simultaneously, the electromagnet is powered on to lower the lever 22 and seal the vent for discharging the water.
In case of a pressing lid (such as U.S. application No. 459,807), the lid 18 is pressed to consequently press the upper cover 17 and seal the vent 14 of the pump cover 27. In this position, by means of further pressing the lid 18, the pump 10 will pump air into the internal vessel for discharging the water.
The abore-mentioned pneumatic vacuum flask of button switch type can discharge water only by precedingly turning on the switch and then placing a glass or the like under the spout for receiving water. Therefore, respecting this type of vacuum flask, water can not be acquired by directly using a glass to touch the switch. As to the vacuum flask of pressing lid type, two hands are required to discharge the water and thus this type of vacuum flask is more inconvenient to a user.